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1. Field of the Invention
The invention relates generally to the field of computer networking. More particularly, the invention relates to a mechanism for implementing Quality of Service (QoS) in a computer network using dynamic network address assignment.
2. Description of the Related Art
Internet Service Providers (ISPs) typically attempt to differentiate themselves based on price and/or service. Price differentiation, however, tends to be a no win game as it tends to lower margins industry wide. Therefore, future differentiation among ISPs is expected to come from the service side.
As network traffic has become more diverse and bandwidth-intensive, it has become apparent that increased network speed and bandwidth alone will not satisfy the high demands of today network environments. Consequently, much attention has been devoted to mechanisms for providing Quality of Service (QoS). For purposes of this application, xe2x80x9cQuality of Service,xe2x80x9d xe2x80x9cservice level,xe2x80x9d xe2x80x9cclass of service,xe2x80x9d and the like, generally refer to a quantifiable measure of service being provided. The measure of service being provided may be in terms of a packet loss rate, a maximum delay, a committed minimum bandwidth, or a limited maximum bandwidth, for example.
Current mechanisms for providing Quality of Service have several limitations. An example of one current mechanism is Resource Reservation Protocol (RSVP), an Internet Protocolxe2x80x94(IP) based protocol that allows end-stations (clients), such as desktop computers, to request and reserve resources within and across networks. However, RSVP is an end-to-end protocol that merely defines the means of communicating a desired Quality of Service between routers. RSVP is limited in that it is receiver initiated. According to RSVP, the end-station that is receiving the data stream communicates its requirements to an adjacent router and those requirements are passed back to all intervening routers between the receiving end-station and the source of the data stream and finally to the source of the data stream itself. Therefore, it should be apparent that RSVP does not allow the user of the source end-station to express his/her desire for a particular level of service. Consequently, while some ISP customers would be willing to pay for increased levels of service, RSVP does not meet the needs of these ISP customers.
Another recent attempt to facilitate traffic differentiation and prioritization include draft standards specified by the Institute of Electrical and Electronics Engineers (IEEE). The IEEE 802.1 Q draft standard provides a packet format for an application to specify which Virtual Local Area Network (VLAN) a packet belongs to and the priority of the packet. The IEEE 802.1p committee provides a guideline to classify traffic based on a priority indicator in an 802.1Q frame tag. This allows VLANs to be grouped into eight different traffic classes or priorities. The IEEE 802.1p committee does not, however, define the mechanism to service these traffic classes.
In light of the foregoing, what is needed is a way to provide Quality of Service in an ISP""s network environment. In particular, it would be desirable for the ISP to be able to offer its customers various levels of service at different price points.
A method and apparatus are described for providing Quality of Service (QoS) in a network environment in which client connections are maintained for limited periods of time. According to one embodiment, packet forwarding devices of a network are caused to forward packets associated with a client according to a particular class of service associated with the user of the client by assigning a network address to the client based upon the particular class of service.
According to another embodiment, a method of configuring the packet forwarding devices in a network is provided. For each class of service supported, information identifying one or more ranges of network addresses that are to receive a particular measure of service associated with the class of service is communicated to the packet forwarding devices.
Advantageously, by employing various aspects of the present invention an ISP may subdivide its network address space into multiple priority pools, where each priority pool represents a range of network addresses that are to receive a particular level of service. Separately, the ISP may also maintain a mapping of each of its users to one of several different service levels. In this manner, the ISP may dynamically allocate network addresses to clients requesting a connection to the network by selecting an available network address from the appropriate priority pool that corresponds to the service level associated with the user.
Other features of the present invention will be apparent from the accompanying drawings and from the detailed description which follows.